Padlock-type seal with anti-tampering means



March 26, 1968 s. M. MOBERG 3,375,033

PADLOCK-TYPE SEAL WITH ANTI-TAMPERING MEANS Filed May 9, 1966 Fl6.4 FIG 5 fi43O 16 -14 I I INVENTOR:

SIGURD M. MOBE R6 MW United States Patent 3,375,033 PADLOCK-TYPE SEAL WIIH ANTI-TAMPERING MEANS Sigurd M. Moberg, East Orange, N.J., assignor to E. .I. Brooks Company, Newark, N.J., a corporation of New Jerse y Filed May 9, 1966, Ser. No. 548,493

2 Claims. (Cl. 292-320) ABSTRACT OF THE DISCLOSURE A padlock-type of seal includes a U-shaped shackle of stiff, spring-steel wire, having ends fixed to and held within a housing when the seal is locked. An external loop portion of the shackle includes two approximately quartercircular portions adjoining each other at an inwardly extending, sharply-reversely bent portion of the shackle located approximately midway of the opposite limits of the loop portion to localize bending at said reversely bent portion and induce breakage at the latter portion upon an attempt to pull the shackle from the housing. Further assurance that such breakage will occur may be achieved by providing a weakening score in the shackle at the sharply-reversely bent portion.

This invention relates particularly to seals in which a relatively stiff resilient wire serves as a shackle or loop captured securely within a housing to close and lock the loop. The general function of the seal is somewhat similar to the function of a padlock but differs from the latter in that once it has been locked, it cannot be opened except by so breaking or deforming it as to render it incapable of being reused. Such seals are particularly useful and are disclosed herein serving as a padlock for a meter cover although they obviously may be used with other devices which desirably should not be opened except by authorized personnel who, of course, would have a further supply of the seals to replace one that would be broken in opening the device for inspection or the like.

The present invention is an improvement over a somewhat similar type of seal disclosed in my copending application, Serial No. 336,953, filed January 10, 1964. The seal of the present invention, like that of the invention disclosed in the mentioned pending application, has a housing of plastic material, and the arrangement and interaction of the parts is such that the device offers very strong opposition to being opened except in such manner that the housing would be so damaged as to render it lncapable of being reused.

This invention differs from that disclosed in said application in that the wire shackle of the present invention possesses certain characteristics which would defeat an attempt to open the seal without damaging it beyond possible reuse. The invention includes characteristics of the wire shackle which would cause the shackle to break beyond the possibility of being reused in the event of the imposition of any substantial strain upon the shackle and also includes a characteristic of the shackle which opposes use of a tool to pry the seal open without destroying it.

It may be seen, therefore, that an important object of this invention is to provide a padlock-type of seal in which the shackle of the seal possesses characteristics inducing breakage thereof upon the imposition thereon of a substantial strain such as might be employed by one attempting to twist or pull the seal apart.

Another important object is the provision in such a seal of a shackle possessing a characteristic which would present substantial opposition to the use of a prying tool Patented Mar. 26, 1968 ICC The foregoing and perhaps other advantages are achieved in part, according to the present invention, by providing a wire shackle which, in manufacture thereof, is weakened at one or more points to induce breakage of the shackle as a result of any attempt to twist the shackle free of the housing or forcefully to pull the wire shackle out of the housing. Also contributing to said advantages is the inclusion of a knick-weakened, inwardly directed, reverse bend somewhat near to or at a central part of the wire shackle so that a forceful pull upon the shackle, in an attempt to open the seal, would inevitably cause the shackle to break at said reverse bend. Additionally, the wire shackle may be provided with reverse bends at portions thereof which, when the seal is locked, are located inside the seals housing, the relation of these bends to more inwardly located parts of the housing being such as to block insertion of a prying tool into engagement with the shackles hooks in the housing in the event of an effort being made to pry open the seal without damaging it beyond the possibility of reuse.

A preferred embodiment of this invention is illustrated in the accompanying drawing without, however, limiting the invention to that particular embodiment.

In the drawing:

FIG. 1 is an elevational view of the subject seal as applied to a meter,

FIG. 2 is a moderately enlarged, front elevational View of the seal in locked condition.

FIG. 3 is a sectional view of the seal, enlarged over FIG. 2, substantially on the lines 3-3 of the latter figure, the shackle being partly broken off.

FIG. 4 is a front, elevational view of the seal, generally similar to FIG. 2, but showing the seal in open condition; one side portion or leg of the wire shackle being shown in chain lines as in closed position in which entangling of plural similar seals of a supply thereof is prevented, and in full lines as released from closed position to open position in readiness to be applied to an object to be sealed.

FIG. 5 is a central, sectional view substantially on the line 5-5 of FIG. 3, including a showing of a prying portion of an instrument such as might be employed by an interloper in attempting to open the seal without damaging it beyond possible reuse.

FIG. 6 is a view generally similar to FIG. 5 but illustrating the elfect of an attempt to pull the shackle forcefully from the seals housing, this being of a condition- FIG. 7 is an enlarged cross-sectional view substantially on the line 77 of FIG. 2.

It should be noted that in this specification and in the accompanying claims certain terms are employed to have meanings as follows: (1) locked to refer to the seal and its parts in a condition, as shown, for example in FIGS. 2 and 5, in which the wire shackle is a closed loop so anchored within a related housing that it cannot be pulled from the housing without destroying the device, (2) open to refer to the seal with one end of the wire shackle free of the housing, as shown in full lines in FIG. 4, so that the shackle can be applied to an object to be sealed, and (3) closed to refer to the closed but nonlocked condition of the wire shackle as shown in chain lines in FIG. 4.

The illustrated seal comprises a Wire shackle 10 and a housing 12. The shackle should be of stiff spring-steel wire, preferably about .045 to .050 inch thick, the wires characteristics, in any event, being such that the device will function as hereinafter described. The housing should preferably be of plastic material which gives it such rigidity as to hold portions of the wire shackle locked therewithin against possible removal therefrom without so damaging the device as to render it non-reusable.

The shackle is formed with a relatively short free leg 14, a relatively long anchored leg 16 and a loop portion 13 integrally interconnecting the two legs. Said legs, respectively, are bent inwardly at their ends to form detents in the form of reversely bent hooks, reversed end portions and 22 of which diverge from an adjacent portion of the shackle.

The housing 12 may be formed of plastic material which is suitable in the sense of enabling the housing to cooperate with the wire shackle in the manner hereinafter set forth. The housing material may, for example, be polyethylene which molds to a hardness of approximately 95 on the durometer scale.

The housing 12, in the form illustrated, is generally rectangular in shape, and its bottom is somewhat rounded. It is approximately three times the thickness of the wire used for the shackle 10 and is formed with two identical pockets 24 and 26, only slightly wider, from front to back, than the thickness of the shackle wire, and symmetrically disposed toward opposite sides of the housing. These pockets are separated by an inner rib 28 on opposite sides of which are formed notches 24a, 24b, 24c and 26a, 26b and 260, disposed in three pairs; the constituents of each pair being in a common plane extending transversely of the housing.

The mentioned notches may be formed, as an incident of the molding of the housing, by small transverse ridges provided on inner mold members which form the pockets 24, 26; said members being withdrawn from said pockets as soon as the molded material commences to solidify. At that time, the material will yield sufiiciently to permit withdrawal of the mold members and then will go back to its shape as initially molded. Thus, the housing can be formed in a single molding operation.

The housing also is formed with lateral flanges at the top of each side wall. These flanges strengthen the top of the housing and facilitate handling and locking of the seal.

The seal, as delivered by the manufacturer to the user, is as shown in FIG. 4 with the wire shackle in its condition, as indicated in broken and chain lines, in which the end of hook 22 of the shackles leg 16 is seated within notch 24a and a knee portion of hook 20 projects into the upper end of pocket 26 of the housing Without being locked therewithin. The end of hook 20, at that time, projects from the housing so that, when the seal is to be applied to some object such as, for example, a hasp assembly 60 on a meter cover 62 (FIG. 1), the leg 14 can easily and quickly be manually sprung clear of the housing to its condition as shown in full lines in FIG. 4.

The leg 14 is then pushed through a hasp eye 64 of the hasp assembly, after which the knee of hook 20 is reinserted in the upper end of the pocket 26. After the seal has been thus applied to the hasp assembly, the housing 12 is pushed upwardly in relation to the shackle to cause the latters hook 22 to slide downwardly in pocket 24 from notch 24a into notch 240 (FIG. 5) and to cause hook 20 of the shackle to slide downwardly in pocket 26 to seat the end of the latter hook into notch 26b. During this sliding, said hooks become compressed to some extent whereafter they expand, due to the resiliency of the shackle wire, so that the ends of said hooks seat firmly within the latter two notches to lock the device.

After such locking, the device ordinarily cannot be opened without incapacitating it for further use due to the fact that, if one attempts to open the seal by forcibly pulling the wire shackle from the casing, the ends of the hooks 20 and 22 burrow into the plastic material of the rib 28 from notches 26b and 24c. The hooks, because of their angular attitude when the device is locked, as in FIG. 5, and because of the character of the wire and of 4 the housing material, tend to burrow more deeply into the rib 28 as such a pulling force is increased. The more deeply such burrowing progresses, the more support is derived by the hooks from the surrounding plastic material of the housing to prevent collapse and withdrawal of the books from the housing.

The just-described arrangement wherein a forcible pull upon the shackle causes the hooks of the shackle to burrow into the plastic material of the housing is disclosed in my said copending application Ser. No. 336,953.

The present invention. however, is directed to such a seal having an improved wire shackle which (1) opposes the use of any tool for insertion into the housing in an effort to open the seal without breaking it, and (2) causes the wire shackle to break if it is forcefully pulled, twisted or bent in an attempt to open the seal.

The shackle 10 according to the present invention possesses one or more of several characteristics as follows, (1) reversely and inwardly bent portions 32 on the legs 14 and 16 of the shackle at points thereon which will be entirely within the housing 12 in tool blocking position when the seal is locked, (2) a reversely, inwardly bent portion 34 of loop portion 18, (3) weakening knicks or scores 36 in the legs 14 and/or at a point or points which, when the seal is locked, will be approximately at the top surface of the housing 12, and (4) a weakening knick or score 38, approximately at the center of the reversely inwardly bent portion 34 of the shackles loop portion 18.

An interloper, probably not being familiar with the nature of the locking parts of the seal, might attempt to loosen the shackle, to open the seal, by twisting its exposed loop portion 18 relatively to the housing 12, or he might try to loosen the shackle by bending it to one side or the other. Such twisting or bending, however, would cause the shackle to break at one or both of the knicks 36 so that the seal could not be restored to its original condition to cover-up the tampering.

An effort to open the seal without breaking it might take the form of an attempt forcefully to pull one of both legs of the shackle from within the housing. Such an attempt, of course, would cause the hooks 20 and 22 to burrow to some extent into the material of the housing as indicated in FIG. 6; but the present invention recognizes that in rare instances such a pull upon the shackle might fail to prevent the removal of one of the shackles legs from the housing and still leave the seal in condition for reuse. According to the present invention, however, the reversely bent portion 34 in the shackle together with the weakening knick or score 38 in that reversely bent portion operates to cause the shackle loop 18 to break before one could possibly succeed in pulling a leg of the shackle from within the housing.

One attempting to pull a leg of the shackle from within the housing would have to exert a very strong or forcefull pull, and, in order to impose such a pull upon the wire of the shackle, would probably employ his finger or a bar which could be comfortably grasped to pull open the seal. The finger or bar would ordinarily be extended through the loop of the shackle 10 at a point therein marked x in FIG. 6. The finger or bar then would be pulled upwardly as indicated by an arrow in said figure to exert the desired pull upon the shackle. The effect of said pull, however, would be to induce straightening of the reversely bent portion 34 whereupon said portion would immediately break at the knick or score 38, thereby rendering the seal incapable of being reused.

An interloper who has some conception of the internal structure of the seal might attempt to employ a prying instrument to open the seal without breaking it.

A prying end of such an instrument 40 is shown in chain lines in FIG. 5, partly projected into pocket 26 in an effort to pry the hook 20 clear of the rib 28 to permit leg 14 to be pulled out of the housing. However, as may be seen in that figure, the reversely bent portion 32 of the leg 14 blocks the pocket 26 to prevent the instrument 40 from reaching the extremity of the hook 20, thereby preventing the opening of the seal.

Thus, it will be seen that, according to the present invention, means are provided which cause the shackle to break at one or more places as a result of a tampering effort, and also includes means preventing successful use of an instrument in an effort to open the seal while still leaving it in condition for reuse.

An in-terloper, desiring to commit theft or to tamper with a sealed device, often wishes to avoid leaving evidence of tampering with the seal. As he, ordinarily, would not have a similar replacement seal, the use of seals according to this invention defeats efforts to coverup his activities.

However, one authorized to remove such a seal for servicing of a device or for other proper purposes, merely breaks the wire shackle to remove the seal. Having a suitable supply of similar seals, he applies a new seal to the device upon completion of his service work thereon.

It will be realized that seals according to this invention are so inexpensive that they may be discarded after a single use.

It will be clear, also, that the concepts disclosed herein may be put into practice in various other ways without, however, departing from this invention as set forth in the accompanying claims.

I claim:

1. A padlock-type seal comprising a housing and a generally U-shaped shackle of stiff, spring-steel wire, one of the opposite legs of said shackle being securely anchored to said housing and the other of said legs extending into the housing when the seal is locked, leaving a generally semi-circular loop portion exteriorly of the housing, said loop portion including two approximately quarter-circular portions adjoining each other at an inwardly extending, sharply-reversely ibent portion of the shackle located approximately midway of the opposite limits of said p portion, where force would be effective in an attempt to pull the shackle from the housing, said reversely bent portion serving to localize bending thereat to induce breakage of the shackle at the latter portion upon the occurrence of such an attempt.

2. A seal according to claim 1, said shackle having a transverse weakening score therein, at said sharplyreversely bent portion, to provide greater assurance of the occurrence of said breakage.

References Cited UNITED STATES PATENTS 402,125 4/1889 Abbott 2923 17 503,110 8/1893 Denney 292-320 523,382 7/ 1894 Sturtevant 292318 884,604 4/1908 Murray 292320 1,011,231 12/1911 Mount 292-321 1,626,273 4/ 1927 Dietze 292-328 1,878,991 9/1932 Murray 292--320 1,943,988 l/1934 Peake 292318 1,964,897 7/ 1934 Wenk 292328 2,020,198 11/1935 Miller 292320 3,186,047 6/ 1965 Schwester 24--l6 MARVIN A. CHAMPION, Primary Examiner.

E. J. MCCARTHY, Assistant Examiner. 

